module Make:
Functor building an implementation of the weak hash set structure.
H.equal
can't be the physical equality, since only shallow
copies of the elements in the set are given to it.
Parameters: 

type
data
The type of the elements stored in the table.
type
t
The type of tables that contain elements of type data
.
Note that weak hash sets cannot be marshaled using
output_value
or the functions of the Marshal
module.
val create : int > t
create n
creates a new empty weak hash set, of initial
size n
. The table will grow as needed.
val clear : t > unit
Remove all elements from the table.
val merge : t > data > data
merge t x
returns an instance of x
found in t
if any,
or else adds x
to t
and return x
.
val add : t > data > unit
add t x
adds x
to t
. If there is already an instance
of x
in t
, it is unspecified which one will be
returned by subsequent calls to find
and merge
.
val remove : t > data > unit
remove t x
removes from t
one instance of x
. Does
nothing if there is no instance of x
in t
.
val find : t > data > data
find t x
returns an instance of x
found in t
.
Not_found
if there is no such element.val find_opt : t > data > data option
find_opt t x
returns an instance of x
found in t
or None
if there is no such element.
val find_all : t > data > data list
find_all t x
returns a list of all the instances of x
found in t
.
val mem : t > data > bool
mem t x
returns true
if there is at least one instance
of x
in t
, false otherwise.
val iter : (data > unit) > t > unit
iter f t
calls f
on each element of t
, in some unspecified
order. It is not specified what happens if f
tries to change
t
itself.
val fold : (data > 'a > 'a) > t > 'a > 'a
fold f t init
computes (f d1 (... (f dN init)))
where
d1 ... dN
are the elements of t
in some unspecified order.
It is not specified what happens if f
tries to change t
itself.
val count : t > int
Count the number of elements in the table. count t
gives the
same result as fold (fun _ n > n+1) t 0
but does not delay the
deallocation of the dead elements.
val stats : t > int * int * int * int * int * int
Return statistics on the table. The numbers are, in order: table length, number of entries, sum of bucket lengths, smallest bucket length, median bucket length, biggest bucket length.